Make the peanut dipping sauce: Mix all the ingredients, whisking in 1/3 to ½ cup warm water to dipping consistency. Add salt to taste. Set aside.
Soak the bean noodles in hot water (120°F, almost too hot to touch) for about 30 minutes, until soft and pliable. Drain thoroughly.
Have all the ingredients arranged nearby, in assembly line fashion: Prepare a glass pie plate or shallow bowl of hot water, 110-120°F. (see note) Lay a clean kitchen towel next to the water and dinner plates on the other side, followed by the fillings and sauces.
Slip a sheet of rice paper into the warm water and soak about 10 seconds, just until soft and flexible. It will become a bit more pliable as it rests so don’t leave it in too long. (see note)
Lay the softened rice paper on the tea towel.
Place a lettuce leaf on the bottom two-thirds of the rice paper, leaving a 2-inch border. Add a portion of noodles towards the bottom of the lettuce, top with a portion of green onions, cucumber, avocado and carrots. Layer in a baked tofu strip, if using. Tuck the fresh herb leaves above the lettuce, directly touching the rice paper so they will be visible on the outside of the rollup. (see note)
Fold the bottom 2-inch border of the rice paper over to enclose the vegetables, as snugly as you can without tearing the rice paper. Fold in the side edges, and then roll to the end, keeping everything fairly tight.
Serve with peanut dipping sauce and purchased sweet red chili sauce mixed with a squeeze of lime.